Environmental friendly cutting fluids and cooling techniques in machining: a review

Atmospheric-pressure plasmas (APPs) have attracted great interest and have been widely applied in biomedical applications, as due to their non-thermal and reactive properties, they interact with living tissues, cells and bacteria. Various types of plasma sources generated at atmospheric pressure have been developed to achieve better performance in specific applications. This article presents an overview of the general characteristics of APPs and a brief summary of their biomedical applications, and reviews a wide range of these sources developed for biomedical applications. The plasma sources are classified according to their power sources and cover a wide frequency spectrum from dc to microwaves. The configurations and characteristics of plasma sources are outlined and their biomedical applications are presented.

https://iopscience.iop.org/article/10.1088/0963-0252/21/4/043001/pdf

Atmospheric-pressure plasma sources for biomedical applications

The generalization of the Local Density Approximation (LDA) method for the systems with strong Coulomb correlations is presented which gives a correct description of the Mott insulators. The LDA+U method is based on the model hamiltonian approach and allows to take into account the non-sphericity of the Coulomb and exchange interactions. parameters. Orbital-dependent LDA+U potential gives correct orbital polarization and corresponding Jahn-Teller distortion. To calculate the spectra of the strongly correlated systems the impurity Anderson model should be solved with a many-electron trial wave function. All parameters of the many-electron hamiltonian are taken from LDA+U calculations. The method was applied to NiO and has shown good agreement with experimental photoemission spectra and with the oxygen Kα X-ray emission spectrum.

http://absimage.aps.org/image/MAR06/MWS_MAR06-2005-007233.pdf

First-principles calculations of electronic structure and spectra of strongly correlated systems: the LDA+U method

Study on microstructure, mechanical properties and machinability of efficiently additive manufactured AISI 316L stainless steel by high-power direct laser deposition

Aluminum Metal Matrix Composites (MMCs) sought over other conventional materials in the field of aerospace, automotive and marine applications owing to their excellent improved properties. These materials are of much interest to the researchers from few decades. These composites initially replaced Cast Iron and Bronze alloys but owing to their poor wear and seizure resistance, they were subjected to many experiments and the wear behavior of these composites were explored to a maximum extent and were reported by number of research scholars for the past 25 years. In this paper an attempt has been made to consolidate some of the aspects of mechanical and wear behavior of Al-MMCs and the prediction of the Mechanical and Tribological properties of Aluminum MMCs.

/pdf/mechanical-and-tribological-behavior-of-particulate-4x05huiioi.pdf

Mechanical and Tribological Behavior of Particulate Reinforced Aluminum Metal Matrix Composites – a review

Tool wear is accelerated with the friction in the tool–workpiece contact during dry cutting. Tool changing early or late will affect the quality of tool and workpiece. An online and machine system vision-based is built to monitor tool condition in real time. MATLAB is used to compile the self-matching algorithm, which considers the features of interested targets on the flank face. Furthermore, a corresponding GUI is designed and encapsulated for both the bottom and flank edges. It is shown that the absolute value of the error on the maximum wear width is not more than 0.007 mm for the bottom edge. For the flank edge, the absolute value of the error is not more than 0.030 mm owing to the local highlighting interference. It is proved that the system can guarantee the quality of tool and workpiece and avoid unnecessary waste significantly. This platform can enhance the utilization of the tool in dry cutting.

An online tool wear detection system in dry milling based on machine vision

In this paper, a novel variable stiffness mechanism (VSM) based on specially designed S-springs made from shape memory alloy (SMA) is developed. Based on the stiffness model, by changing the state combination of the SMA S-springs with different thicknesses, the actuator’s stiffness can be discretely adjusted online. The stiffness adjustment range of the actuator can be conveniently extended almost from 0 N/m to infinity by changing the preset spring angle manually offline without a complex mechanical mechanism or replacing any parts. A linear digital variable stiffness actuator (LDVSA) is also designed with the VSM. Some tests of the SMA S-springs, as well as the actuator’s stiffness under different configurations, comparisons with other actuators and its trajectory tracking capacity are conducted to verify its design. Then, a dynamic model of the actuator is established and its bandwidth is analysed. Based on this, explosive experiments are designed and performed to explore the application potential of the actuator. Experimental results are provided to illustrate the explosive capacity and energy efficiency of the proposed design.

/pdf/design-and-analysis-of-a-linear-digital-variable-stiffness-4xiez7kdnr.pdf

Design and Analysis of a Linear Digital Variable Stiffness Actuator

The mechanism of micro-milling modeling for aluminum alloy 7050-T745 is to be investigated, and a finite element model for micro-milling that reflects the actual state of the three-dimensional micro-milling is built by adopting the software of ABAQUS/Explicit. Experiment is conducted to verify the validation of the model. Simulated chip morphology in different cutting parameters agrees to the experimental results very well. Based on the FE model, cutting stresses, equivalent plastic strains, temperatures distribution and cutting forces are obtained and analyzed. This provides a good method to investigate the micro milling principles.

Experiments and Finite Element Simulations on Micro-Milling of Aluminium Alloy 7050-T7451

In atmospheric pressure plasma treatments water molecules in the substrate material may disrupt the molecular arrangement in the substrate and thus greatly influence the outcome of the plasma treatment This paper summarizes the results of our recent studies on how moisture influences the etching, surface chemical modification, crystallinity and aging of aramid, ultrahigh molecular weight polyethylene (UHMWPE), polyamide fibers, and poly(vinyl alcohol) (PVA) films Overall, a higher moisture regain often results in a greatly enhanced etch rate, less surface chemical composition change, increased near-surface crystallinity, which could lead to a higher surface wettability, higher interfacial shear strength between the fibers and resin, decreased water solubility for PVA films, and delayed hydrophobic recovery of plasma treated fibers Therefore, it is important to control the moisture contained in the substrate in atmospheric pressure plasma treatments

Influence of Moisture on Effectiveness of Plasma Treatments of Polymer Surfaces

According to the technical problems such as low stiffness vibration and dimension error in milling Ti6Al4V thin-walled component, the manufacturing with paraffin reinforcement is studied. Firstly, paraffin formula for milling thin-walled component is researched. Secondly, applying the finite element method (FEM) to predict the deformation of machining with paraffin reinforcement and the corresponding milling experiments is done to check the the validity of the model. Finally, the influences of machining accuracy about different paraffin formulas for the same component are obtained. This study supplies support for the research of paraffin formula which are based on reducing the distortion of workpiece.

Jie Sun

Papers

An online tool wear detection system in dry milling based on machine vision

Design and Analysis of a Linear Digital Variable Stiffness Actuator

Experiments and Finite Element Simulations on Micro-Milling of Aluminium Alloy 7050-T7451

Influence of Moisture on Effectiveness of Plasma Treatments of Polymer Surfaces

Research on Machining Accuracy in Milling Ti6Al4V Thin-Walled Component with Paraffin Reinforcement